Electricity is supplied to the island from the mainland via undersea cables. Power sockets are two pin and the voltage is 220 so bring an appropriate adaptor/transformer with you for your hair dryer etc. Don't forget that you will need a transformer for radios, cd players and the like if you are coming from the States. The island's supply is good during the summer months but there tend to be a few power cuts in wet weather. Bring a surge protector with you for your laptop.